In the 90s teens used pagers as the original instant messenger
Never underestimate your customers, especially if they are teenagers.
Before cell phones blew up some of us had pagers, and I remember doing this. We had a number of ad-hoc codes that would signal times, locations, and people we were with. It was the original "Short Message Service."
Young power-users will bend your products and services in creative, funny, and frustrating ways.